Guillotine shearing machine, especially for continuous bands, with blades translating parallel, one towards the other, on circular trajectories

ABSTRACT

Guillotine shearing machine, especially for cutting continuous metal bands (90) in which each of the two longitudinal blades (15), (16) counterposed by means of connections to connecting rods (39), (40), (41), (42) each supported by a pair of cranks (31-32), (35-36) and (33-34), (37-38), translates, both parallel to each other, on equal circular trajectories in such a way that one blade (15) encountering the other (16) in proximity to the cutting plane and progressively superimposing each other, effects the cut, speed of the blades (15), (16) in each cycle being regulated according to the sliding speed of the band (90) so that in the zone of contact the speed of the blades (15), (16) coincides with that of the band (90) enabling pieces of band to be cut off in whatever length is desired.

BACKGROUND OF THE INVENTION

The so-named guillotine shearing machine is a well-known tool. Oneblade, generally the upper one, is mobile and slides on runners whichkeep the movement rectilinear and transversal to the cutting plane. Theblade is operated by cams or by hydraulic systems. Shearing machinesused for cutting lengths of sheet metal, profiles, continuous movingbands, comprise a pair of drums between which the band passes, andradially set blades which meet at the shearing plane to cut through themoving piece.

The radial position of the blades obviously determines the angle theyassume, which angle varies progressively during cutting. This means thatthe advantages of speed and simplicity in continuously cutting a movingband are to some extent adversely affected and the operation lacks thatprecision which can only be obtained with blades set perfectlyperpendicular to the piece to be cut. The invention here describedavoids these drawbacks at the same time offering considerable advantagesas will now be explained.

SUMMARY OF THE INVENTION

Subject of the invention is a guillotine shearing machine, especiallyone for cutting continuous metal bands, wherein the opposinglongitudinal blades translate parallel one to another along equalcircular trajectories with parallel axes of rotation lying on the samegeometrical plane. Blade movement is reciprocally synchronized. Thephases in movement of one blade in relation to the other are such thatone blade meets the other close to the shearing plane becomingprogressively superimposed to make the cut.

The start of each cutting cycle, corresponding to a 360° rotation of theblades, is controlled in relation to certain speeds at which the band,or any other piece to be cut, and the blades move during the cycle, andat the most suitable instant for cutting off the desired length of theband.

Blade speed is adjusted according to that of the band to be cut in sucha way that, when the cut is made, the speed of the cutting edgepractically coincides with that of band movement. The blade is moved bymeans of a double pair of cranks for each of the two blades, one pairbeing situated at each end of the blade. The two cranks in each pair areconnected by sprocket wheels with an idling sprocket wheel in betweenthem.

The pairs of cranks at each end of the blade are connected by alongitudinal shaft to ensure synchronized movement, preferably by pairsof gears.

The drive shaft is preferably fixed to the upper crank of the lowerblade, connected to the lower crank of the upper blade by a pair ofsprocket wheels.

Synchronizing shafts between the pairs of cranks for each blade arerespectively connected, by means of gears, to the sprocket wheel fixedto the upper crank of the lower blade, and to the sprocket wheel fixedto the lower crank of the upper blade.

Each blade is fixed at either end to two connecting rods respectivelyconnected to the cranks forming either of the pairs that support each ofthe above blades at both ends.

The connecting rods of the upper blade support an elastic presser actingover the whole width of the translating band, at the moment when theblades meet, accompanying their movement and at the same timestabilizing their vertical position to hold the band relatively steadyin relation to the blades that make the cut.

At the beginning of the cut, said elastic presser is in contrapositionto a support of the band fixed to the lower blade close to the cuttingedge. Therefore, close to the cut and while it is being made, saidsupport causes that part of the band as yet uncut to be raised to theprogressive level of the lower blade where it remains until completionof the cut extending from one longitudinal edge of the band to theother. In so raising the band by means of the support fixed to the lowerblade, speed of the band and of the cutting edge of the lower bladeround its circular trajectory are kept practically equal untilcompletion of the cut.

The start of each shearing cycle to cut off the desired length of band,in each cycle, as well as regulation of blade rotation speed, in eachcycle, according to the speed at which the band moves so that blade andband speeds shall be equal when the blade makes contact with the band,is operated automatically by an electronic control panel which memorizesthe information received from sensors applied to the band and which,according to the speed of band movement and according to a program typedin on a keyboard or by some other means, has one or more shearing cyclescarried out for cutting off one or more equal or different lengths ofband, as desired.

The characteristics and purposes of the invention will be made stillclearer by the following examples of its execution illustrated bydrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Guillotine shearing machine, subject of the invention, seen fromthe front.

FIG. 2 The same machine seen from the back.

FIG. 3 Cross section view of the same machine.

FIG. 4 Diagram to show blade movements.

FIG. 5 Explanatory view showing cutting of a band with upper and lowerblades.

FIG. 6 Explanatory view showing the cut band.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The shearing machine, subject of the invention, comprises a base (10)and uprights (11), (12) connected at the top by the head (43). Eachupright comprises in turn the side pieces (13), (14).

The upper (15) and lower (16) longitudinal blades are respectivelysupported by frames (17), (18), the upper one comprises the bushings(19)-(20) and the lower one comprises the bushings (23-26).

Said bushings house the rotatable pins (27), (28) and (29), (30) of thecranks (31), (32) and (33), (34) which determine the cutting movement ofthe blades.

The extremities of the frames (17) and (18) create a kind of connectingrod (39), (40) and (41), (42) for respectively connecting the pairs ofcranks (31-32), (33-34), (35-36) (37-38).

The drive shaft (50) is fixed to the crank (33) and can rotate on thebearings (51), (52) mounted respectively on the sides (13) and (14) ofthe upright (11).

By means of the sprocket wheel (53) and the opposing sprocket wheel(54), said shaft is similarly fixed to the crank (32) of the upperblade.

By means of the sprocket wheels (55) and (56) with intermediate idlingsprocket wheel (57), the crank (33) is fixed in its movement to thecrank (34).

Therefore, by means of the pins (29) and (30) and the bushings (23) and(24), the pair of cranks (33) and (34) determine the movement of thelower blade (16) in synchrony with the second pair of cranks (37), (38)connected by the connecting rod (42) and by other gears similar to thosealready described for the first pair of cranks.

The crank (32) is connected to the crank (31) by means of the connectingrod (39) realized with the frame (17) and with the connecting rod (41)of the same frame, fixed to the bushings (21) and (22).

Therefore, the cranks (35) and (36) at the other end of the frame (17)for the blade (15) are also made to move by mechanisms substantially thesame as those already described for the lower blade, as the shafts forthe two pairs of cranks respectively, on either side of the upper blade,are connected one to another by sprocket wheels like those alreadydescribed (55), (56) and (57) and of which, for the sake of simplicity,only the sprocket wheel (59) fixed to the shaft of the crank (32) isindicated.

Synchronization of movement of the pairs of cranks (33-34) and (37-38)for the lower blade, and (31-32), (35-36) for the upper blade is ensuredby the two horizontal shafts (70) and (71) supported on bearings like(60), (61) placed on on the sides like (13) and (14) of the uprights(11) and (12). Each of the two shafts is connected to the drive shaft(50) by means of gears like (62), fixed to the shaft (70) that engagewith the sprocket wheel (53) mounted, as already explained, on saidshaft (50).

On the upright (12) the shaft of crank (37) supports another sprocketwheel, not shown in the drawing, that engages a pinion fixed to theother end of the shaft (70) and carries out the same functions as thegear (62).

Mechanisms similar to those already described connect the shafts tocranks (31) and (35) with the longitudinal shaft (71) for synchronizingmovement of the pairs of cranks for the upper blade.

An elastic presser 80 is fixed to the connecting rods (39), (41) of theupper blade. A support 81 substantially levelled with the lower blade16, is fixed to the connecting rods 40, 42 of the lower blade.

FIG. 4 clearly shows the movements made by the upper (15) and lower (16)blades in their various positions as these positions change (15₁),(15₂), (15₃) and respectively (16₁), (16₂), (16₃), due to movement ofthe cranks.

At each shearing cycle the blades start from and return to the upperresting points (15₁) and (16₁).

When they have reached positions (15₃) and (16₃), the blades traveltogether with the band, little by little increasing the amount ofsuperimposition, as they approach their lower resting points (15) and(16), and thus generating the cut.

During the cut (FIG. 5) upper blade 15 passes from position 15₃ toposition 15, while lower blade 16 passes from position 16₃ to position16; superimposing itself on blade 15 and completing the cut begun on oneside of the band when the blades were in position 15₃ and 16₃. In thecurve traced by lower blade 16 to pass from position 16₃ to position 16,band 90 is raised by support 81 (FIGS. 2 and 3), together with blade 16.Thus the band speed at the start of contact with blade 16 remains equalto the circumferential speed of blade 16 until the cut is complete,ensuring the precision of the cut. During this cut support 81 fixed toblade 16 coincides with presser 80 fixed to blade 15. In FIG. 5 it canbe clearly seen that band 90, raised by support 81, which moves to 81',assumes position 90', corresponding to the start of the cut at point A.Because of the rotation of the blades to their respective positions 15and 16, the cut from point A (FIG. 6) to point B is completed. The speedof band 90, identical to that of blade 16 and support 81 during the cutfrom A to B (FIG. 6) ensures that point A moves to A', and thus that thecut BA' is along a YY axis perfectly orthogonal to the XX axis of theband.

The start of each shearing cycle to cut off the desired length of band,as well as regulation of blade rotation speed in each cycle according tothe speed at which the band moves, is operated automatically by anelectric control panel which memorizes the information received fromsensors applied to the band and which, according to the speed at whichit moves, and to a program put in on a keyboard or by some othercontrols, operates one or more cutting cycles for detaching one or moreequal or different lengths of band, as required. The advantages offeredby the invention are evident.

To summarise, though the band is continually moving, clean and precisecuts can be obtained, in the desired lengths, with the blades remainingalways parallel in their cutting movements even though theirtrajectories are circular, and therefore being always transversal to thepiece to be cut.

Compared therefore with the shearing machines at present in use, cuttingis done at a speed and with a degree of precision never before achieved.

As the applications of the invention have been described as examplesonly, not limited to these, it is understood that every equivalentapplication of the inventive concepts explained, and any productmanufactured and/or in operation according to the characteristics of theinvention will be convered by its field of protection.

I claim:
 1. A guillotine shearing machine for cutting continuous metalbands having a considerable width, said guillotine machine comprisingupper and lower blades arranged at an angle to each other; means forsynchronously moving said upper and lower blades towards each other andparallel to each other along circular paths around axes of rotationlying in one and same geometrical plane in such a manner that said upperand lower blades meet, at each cutting cycle after each blade beingrotated by an angle of 360°, in proximity of a cutting plane withgradual superimposition for making a cut, said upper and lower bladeshaving a common speed regulated in such a manner that the common speedcoincides in a zone of contact of said upper and lower blades with theband, with a speed of the band; an elastic presser fixed to the upperblade and acting over an entire width of the band; and a band supportfixed to the lower blade and movable therewith for progressively raisingthe band to maintain the speed of the band equal to the common speed ofsaid blades during an entire cutting time whereby an accurate cut in adirection perpendicular to a direction of band movement is obtained.